Abstract: A chain block is provided including a load chain which hangs a load, and a load sheave member which is rotatably supported between a first frame and a second frame, around which the load chain is wound, and which has a chain pocket in which the load chain goes, the load chain is made of a steel material having the Rockwell hardness C scale (HRC) of 47 to 51, and the load sheave member is made of a steel material in which at least the chain pocket has the Rockwell hardness C scale (HRC) of 40 to 45.

Abstract: A hoist with built-in load sensitive automatic speed change device includes: a high-torque input member coupled to a hand wheel, a magnetic clutch coupled via a speed-increasing mechanism and configured to transmit a low load, and an output transmitting means configured to transmit a rotational operating force of the hand wheel to mechanical brakes via the high-torque input member or magnetic clutch, wherein the hand wheel is axially supported by a drive member coupled to the output transmitting means of the mechanical brakes and rotated thereby, the magnetic clutch is arranged between the speed-increasing mechanism and the hand wheel, the hand wheel and the speed-increasing mechanism are coupled by a hollow input member provided so as to cover the outer periphery of the magnetic clutch, the output transmitting means is fitted onto a boss portion of the drive member so as to allow torque transmission to the boss portion.

Abstract: Detecting circuits are connected in parallel to respective on/off mechanical contacts or on/off semiconductor devices of a motor contactor and/or a brake contactor of a driving circuit supplying driving electric power from a three-phase alternating-current power supply circuit to a three-phase alternating-current electric motor and a brake through the motor contactor and the brake contactor, respectively. The detecting circuits output pulse signals synchronized with the alternating current from the alternating-current power supply circuit. A signal processing circuit processes the pulse signals from the detecting circuits and detects a normal or abnormal condition of each on/off mechanical contact or on/off semiconductor device of the motor contactor and/or the brake contactor.

Abstract: Disclosed is a manual chain block that achieves a more compact overall device and also does not lose the strength of the device itself by means of the position of a reduction gear of a speed reduction mechanism section being able to be positioned closer to the center regardless of the bearing of a load sheave. In the manual chain block, a load sheave (12) is supported rotatably by a first and second primary frame (11a, 11b) by means of bearings (13a, 13b) with axle sections (12a, 12b) therebetween. A supplemental plate (30)—which forms, in the direction of thrust: a bearing hole (33) of an axle section (16br) of a first reduction gear (16b); and a drawn section (31)—is, in a manner so as to supplement the aforementioned first primary frame (11a), disposed at the periphery of the bearing (13a) that supports the axle section (12a) of the load sheave (12) at the first primary frame (11a).

Abstract: Disclosed is a hoist equipped with a power-off type electromagnetic brake, wherein, at positions corresponding to an upper portion and a lower portion of a brake disk of an electromagnetic brake cover surrounding the electromagnetic brake, there are respectively provided insertion openings for first and second operation levers to be vertically inserted between an armature and a pressure-receiving plate. The first operation lever has an insertion portion to be fitted from above into the insertion opening to be inserted between the armature and the pressure-receiving plate, a retaining portion horizontally bent from the insertion portion, and a connection portion downwardly bent from the retaining portion to be connected with the second operation lever, and the second operation lever has an insertion portion fitted from below into the lower insertion opening to be inserted between the armature and the pressure-receiving plate, and an operation portion horizontally bent from the insertion portion.

Abstract: A torque transmission device includes a magnetic pole rotating body having magnetic poles arranged in a row on a circumference thereof; a yoke rotating body configured to rotate about the same center axis of rotation as the magnetic pole rotating body and including tooth-shaped portions arranged in a row so as to oppose the magnetic poles; and a side magnetic body formed of a magnetic material provided on the side of the tooth-shaped portions of the yoke rotating body, wherein the magnetic pole rotating body and the yoke rotating body are supported so as to be rotatable about the direction of center axis of rotation and so as to allow the magnetic poles and the side magnetic body to be relatively movable in the direction toward and away from each other along the center axis of rotation.

Abstract: Provided is a chain block with which wheel cover strength can be improved while inhibiting an increase in cost, without the need for separate reinforcement members. A chain block is provided with a wheel cover which is attached to a frame member, and which covers a hand-chain wheel having a hand chain looped thereover. A plurality of fixation holes for having fixation members inserted therethrough during attachment to the frame member are provided in peripheral edge sections of end-surface sides of the wheel cover, said end-surface sides being disposed facing the frame member. Wrap-around portions are provided to wheel-cover side surfaces which intersect the end surfaces, said wrap-around portions being formed so as to surround, at an angle exceeding 90, the fixation holes in the peripheral direction of the fixation holes.

Abstract: A hoist with a regenerative resistor contains the following in a casing: a load-raising/lowering motor driven by an inverter control device and provided with a forced-cooling means; and a mechanism part containing a reduction mechanism part and a load sheave that uses power from the reduction mechanism part to take up and let out a chain. The load-raising/lowering motor, mechanism part, inverter control device, and regenerative resistor are distributed inside the casing to achieve a balance of weight about the center of gravity of the load applied when raising or lowering. Also, the inverter control device and the regenerative resistor are affixed to the casing, in close contact therewith, in parts of the casing separated from each other with the mechanism part therebetween.

Abstract: A variable-speed hoisting machine uses an electric motor having a pull-rotor brake as a hoisting motor and capable of supplying the electric motor with an electric current that can reliably release the pull-rotor brake at the time of starting an operation even in the case of a variable-speed hoisting machine such as an electric chain block in a variable-speed hoisting machine having an electric motor with a pull-rotor brake and an inverter controlling the speed of the electric motor in a soft-start manner, the inverter is set to operate according to a predetermined voltage-frequency (V-F) pattern.

Abstract: A chain connection link includes: a pair of U-shaped links of a U-shaped configuration in front view and each having two arms; a connection arm portion provided at an end portion of one arm of each of these U-shaped links; a connection groove-shaped arm portion having a groove and provided at an end portion of the other arm of each of these U-shaped links; and through-holes provided in the connection arm portion and the connection groove-shaped arm portion, the connection arm portion of one U-shaped link being fit-engaged with the connection groove-shaped arm portion of the other U-shaped link, a connection shaft being passed through the through-holes to connect the pair of U-shaped links, wherein the size of the outer periphery of the connection groove-shaped arm portion is larger than the size of the outer periphery of the connection arm portion.

Abstract: A load sensitive magnetic clutch device includes: a magnetic pole rotating body having magnetic poles arranged on the circumference thereof and provided with a clutch projection of a claw clutch at an end thereof; a yoke rotating body configured to rotate about an axial center of rotation identical to that of the magnetic pole rotating body; and a high-torque input member configured to rotate about the identical axial center of rotation and having a clutch engaging portion engaging the clutch projection. The clutch projection is formed of a magnetic body. The clutch engaging portion includes a clutch retaining magnetic body configured to attract the clutch projection by a magnetic force. The clutch projection is attracted by the clutch retaining magnetic body by an application of a load torque exceeding a torque which is transferrable between the magnetic pole rotating body and the yoke rotating body.

Abstract: A load weight determining apparatus and method for an electric chain block having a lifting-lowering motor and an inverter controller. The lifting-lowering motor rotates a sheave to wind up and unwind a chain engaging the sheave. The load weight determining apparatus has a current detecting element detecting a motor current supplied to the lifting-lowering motor from the inverter controller, and a load weight determining unit. A torque current is calculated from the motor current detected by the load weight determining unit, and a variation cycle of the torque current is calculated. An average torque current value over a period of time corresponding to the variation cycle is calculated, and the average torque current value is compared with a set threshold to perform load weight determination.

Abstract: A non-excited operation type electromagnetic brake control device and method which are free from vibration noise and frequent switching when reducing average current which flows through a brake coil in a holding state of a non-excited operation type electromagnetic brake are provided. An acute triangle voltage wave generation unit generates a stepped acute triangle voltage wave which is formed by valley parts with a first angle and peak parts with a second angle smaller than the first angle arranged alternatively. A comparative voltage wave generation unit generates a comparative voltage wave based on current which flows through the brake coil. A comparison unit compares the acute the triangle voltage wave with the comparative voltage wave when the non-excited operation type electromagnetic brake is in the holding state.

Abstract: A wet friction plate is constructed such that a carbon based friction material is placed on an outer peripheral side of a friction plate and a paper based friction material is placed on an inside of a carbon based friction material. A transmission torque occupied by the paper based friction material is smaller than that occupied by the carbon based friction material. The wet friction plate can prevent a sudden unexpected slip at low temperature.

Abstract: A control device for a hoist, which enables easy judgment of the lifetime of a brake of a hoist is provided. The time setting unit sets the time from startup of a double winding induction motor to disengagement of the brake and the time from start of engagement of the brake to stopping of the double winding induction motor in accordance with the time from the startup of the double winding induction motor to generation of torque. The time changing unit detects if power-supply frequency of a power supply is 50 Hz or 60 Hz and can change at least one of the time from the startup of the double winding induction motor to the disengagement of the brake and the time from stopping of driving of the brake to stopping of double winding induction motor in accordance with the power-supply frequency of the power supply.